Reduced primary care respiratory infection visits following pregnancy and infancy vitamin D supplementation: A randomised controlled trial

Abstract

Aim To determine whether vitamin D supplementation reduces primary care visits for acute respiratory infection (ARI). Methods A randomised, double-blind, placebo-controlled trial was conducted in New Zealand and powered to determine the vitamin D dose needed to achieve normal vitamin D status during infancy. Healthy pregnant women, from 27 weeks' gestation to birth, and their infants, from birth to age 6 months, were assigned to placebo or one of the two dosages of daily oral vitamin D3. Woman/infant pairs were randomised to placebo/placebo, 1000 IU/400 IU or 2000 IU/800 IU. For this ad hoc analysis, the primary care records of enrolled children were audited to age 18 months. Results Two hundred and sixty pregnant women were randomised to placebo (n = 87), lower-dose (n = 87) or higher-dose (n = 86) vitamin D3. In comparison with the placebo group (99%), the proportion of children making any ARI visits was smaller in the higher-dose (87%, p = 0.004), but not the lower-dose vitamin D3 group (95%, p = 0.17). The median number of ARI visits/child was less in the higher-dose vitamin D3 group from age 6-18 months (placebo 4, lower dose 3, higher dose 2.5; p = 0.048 for higher-dose vitamin D3 vs. placebo). Conclusion Vitamin D3 supplementation during pregnancy and infancy reduces primary care visits for ARI during early childhood.